The present invention relates to flow regulators and particularly flow regulators employed for compressible fluid flow control and more particularly relates to such regulators which are supplied with a fluid pressure signal which is modulated by an electrically remote controlled bleed valve for controlling the pressure applied to one side of a pressure responsive member. Regulators of this type typically have a moveable valve member attached to the opposite side of the pressure responsive member for controlling flow over a valve seat of the compressible fluid to be flow regulated.
Regulators of this type are utilized in motor vehicle fuel vapor emission control systems for controlling flow from a fuel vapor purge canister for communication with the charge air inlet of the vehicle engine. Purge control regulators of this type are known to utilize the engine manifold depression or vacuum as a fluid pressure signal source for the regulator.
In such known fuel vapor purge system flow regulators, problems have been experienced at certain levels of pressure in the vapor canister and at certain flow conditions in a connecting conduit between the canister and the flow regulator valve inlet. For a given length of conduit, pulses and rarefactions in the flow conduit have produced a standing wave which causes vibration of the pressure responsive member which in turn has produced a resonance in the conduit with the resultant tuning of the conduit. This resonating of the conduit between the fuel vapor canister and the regulator valve has produced an audible phenomenon known as "hooting" which is an undesirable noise in the system from the vehicle occupants' standpoint.
Thus, it has been desired to provide a way or means of dampening pressure pulsations or rarefactions in the inlet of a flow regulator and to provide such dampening in a way that is low in manufacturing costs and does not adversely affect the function or calibration of the flow regulator.